drivers/hid/hid-picolcd_lcd.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /***************************************************************************
   3  *   Copyright (C) 2010-2012 by Bruno Prémont <[email protected]>  *
   4  *                                                                         *
   5  *   Based on Logitech G13 driver (v0.4)                                   *
   6  *     Copyright (C) 2009 by Rick L. Vinyard, Jr. <[email protected]>   *
   7  *                                                                         *
   8  ***************************************************************************/
   9
  10 #include <linux/hid.h>
  11
  12 #include <linux/fb.h>
  13 #include <linux/lcd.h>
  14
  15 #include "hid-picolcd.h"
  16
  17 /*
  18  * lcd class device
  19  */
  20 static int picolcd_get_contrast(struct lcd_device *ldev)
  21 {
  22         struct picolcd_data *data = lcd_get_data(ldev);
  23         return data->lcd_contrast;
  24 }
  25
  26 static int picolcd_set_contrast(struct lcd_device *ldev, int contrast)
  27 {
  28         struct picolcd_data *data = lcd_get_data(ldev);
  29         struct hid_report *report = picolcd_out_report(REPORT_CONTRAST, data->hdev);
  30         unsigned long flags;
  31
  32         if (!report || report->maxfield != 1 || report->field[0]->report_count != 1)
  33                 return -ENODEV;
  34
  35         data->lcd_contrast = contrast & 0x0ff;
  36         spin_lock_irqsave(&data->lock, flags);
  37         hid_set_field(report->field[0], 0, data->lcd_contrast);
  38         if (!(data->status & PICOLCD_FAILED))
  39                 hid_hw_request(data->hdev, report, HID_REQ_SET_REPORT);
  40         spin_unlock_irqrestore(&data->lock, flags);
  41         return 0;
  42 }
  43
  44 static const struct lcd_ops picolcd_lcdops = {
  45         .get_contrast   = picolcd_get_contrast,
  46         .set_contrast   = picolcd_set_contrast,
  47 };
  48
  49 int picolcd_init_lcd(struct picolcd_data *data, struct hid_report *report)
  50 {
  51         struct device *dev = &data->hdev->dev;
  52         struct lcd_device *ldev;
  53
  54         if (!report)
  55                 return -ENODEV;
  56         if (report->maxfield != 1 || report->field[0]->report_count != 1 ||
  57                         report->field[0]->report_size != 8) {
  58                 dev_err(dev, "unsupported CONTRAST report");
  59                 return -EINVAL;
  60         }
  61
  62         ldev = lcd_device_register(dev_name(dev), dev, data, &picolcd_lcdops);
  63         if (IS_ERR(ldev)) {
  64                 dev_err(dev, "failed to register LCD\n");
  65                 return PTR_ERR(ldev);
  66         }
  67         ldev->props.max_contrast = 0x0ff;
  68         data->lcd_contrast = 0xe5;
  69         data->lcd = ldev;
  70         picolcd_set_contrast(ldev, 0xe5);
  71         return 0;
  72 }
  73
  74 void picolcd_exit_lcd(struct picolcd_data *data)
  75 {
  76         struct lcd_device *ldev = data->lcd;
  77
  78         data->lcd = NULL;
  79         lcd_device_unregister(ldev);
  80 }
  81
  82 int picolcd_resume_lcd(struct picolcd_data *data)
  83 {
  84         if (!data->lcd)
  85                 return 0;
  86         return picolcd_set_contrast(data->lcd, data->lcd_contrast);
  87 }
  88